Sir Keir Starmer’s government is expected to announce a ban on gas boilers in new homes by 2027 – he is seen here at a housing development in Walthamstow, east London, in August 2022

A bombshell report earlier this year revealing that the uptake of heat pumps to replace boilers had been less than half the expected levels

Uncertainty over the role hydrogen could play in heating homes is also hampering investment, the report found.

The total installed in 2022 was just 55,000, well short of the Government’s targets of 600,000 by 2028 and 1.6million by 2035.

The Financial Times has reported that the proposed ban on gas boilers in new homes would involve a 12-month delay to ensure housebuilders are prepared for the switchover.

The previous Conservative administration last year launched a consultation on the Future Homes Standard policy.

New legislation had been expected to be announced this month but has been put back by at least half a year following the general election last July, according to the Telegraph.

The plans form part of a mission to cut carbon emissions across all new homes by up to 80 per cent – but there have been concerns over whether enough new heat pumps can be supplied to meet targets.

Sir Keir’s government has also pledged to build 300,000 new homes per year.

Steve Turner, executive director of the Home Builders Federation lobby group, said: ‘We need to make sure the heat pump supply chain will be in place.

The Government has set a target of installing 600,000 electric heat pumps by 2028

The Prime Minister Sir Keir Starmer, then opposition leader, is seen here inspecting heat pump units in the roof of a housing development in Walthamstow, east London, in August 2022

‘At the minute, we’re only installing about 35,000 a year – to go from there to up to 300,000 a year, plus additional ones fitted to existing homes, the supply chain will need a significant scale-up.’

He also raised fears over the capacity of the National Grid if put under extra pressure to serve heat pumps.

He said: ‘If you’re not using gas for heating, that will load more on to the grid. We need to make sure there’s enough resilience within that.’

It has previously been suggested that all new homes should be without boilers by the end of 2030.

Officials are also encouraging wider use of solar panels, although these are not expected to become mandatory.

A spokesman for the Department of Housing, Communities and Local Government said: ‘We remain committed to delivering highly efficient new homes that will become net zero as the grid decarbonises.

‘We are considering the responses to the Future Homes Standard consultation and will respond in due course.’

A study published last month found that British homeowners are being put off installing environmentally-friendly heat pumps by the high cost which has not reduced over the past decade.

An air source heat pump unit is installed into a 1930s built house in Folkestone, Kent, in 2021

A study published the average cost of installing air source heat pumps (ASHPs, in blue) and ground source heat pumps (GSHPs, in orange) – combining both historic and forecast data

Researchers said the systems only play a ‘marginal role’ in heating UK homes – and installation numbers remain low compared to traditional, fossil fuel-based systems.

An average air source heat pump costs about £10,000 while a ground source one is £20,000, the academics estimated – figures which have hardly changed since 2010.

The analysis by the University of Edinburgh and Imperial College London said the high costs meant ambitious Government targets for installations would be missed.

Projections suggest a fall of 20 to 25 per cent in installation costs by 2030, but the study said this also ‘falls significantly short of the targets’ set by the Government.

The experts said it costs an average of £3,000 to install a traditional gas boiler – 30 per cent of the average price of air source pumps and 15 per cent of ground source.

Ignoring any available Government grants or loans, achieving cost parity with air source heat pumps would therefore require a 70 per cent drop in installation costs.

The Government’s Boiler Upgrade Scheme offers grants of £7,500 towards a heat pump – a greener alternative to a gas boiler which takes heat from outside and pumps it back into buildings to warm them up.

The study concluded that Government policies should be based on ‘realistic assessments of likely cost reductions’, and ‘develop incentives that can address the relatively high upfront costs of some low carbon technologies’.

Heat pumps run on electricity and capture heat from outside before transferring it inside

An air-source heat pump in front of a cottage in Newbiggin-on-Lune, Cumbria, in February

Air source heat pumps absorb heat from the outside air at low temperature into a fluid to heat your house and hot water. They are able to extract renewable heat from the environment

Ground source heat pumps circulate a mixture of water and antifreeze around a ground loop pipe. Heat from the ground is absorbed into the fluid, then passes through a heat exchanger

Advocates of heat pumps say they offer energy security and efficiency benefits and can also lower energy bills.

But homeowners who have installed the systems have complained that their monthly bills skyrocketed during the energy crisis.

A report by innovation charity Nesta in July found one in 10 households – around three million homes – need to install heat pumps or other low carbon heating during this parliament to meet climate targets.

It also revealed that the UK installed only an estimated 250,000 heat pumps between 2020 and 2024, while 25.5million homes still use oil or gas boilers.